The German PCL-5: evaluating structural validity in a large-scale sample of the general German population

ABSTRACT

Background: In attempts to elucidate PTSD, recent factor analytic studies resulted in complex models with a proliferating number of factors that lack psychometrical and clinical utility. Recently, suggestions have been made to optimize factor analytic practices to meet a refined set of statistical and psychometric criteria.

Objective: This study aims to assess the factorial structure of the German version of the PCL-5, implementing recent methodological advancements to address the risk of overfitting models. In doing so we diverge from traditional factor analytical research on PTSD.

Method: On a large-scale sample of the German general population (n = 1625), exploratory factor analyses were run to investigate the dimensionality found within the data. Subsequently, we validated and compared all model suggestions from our preliminary analyses plus all standard and common alternative PTSD factor models (including the ICD-11 model) from previous literature with confirmatory factor analyses. We not only consider model fit indices based on WLSMV estimation but also deploy criteria such as favouring less complex models with a parsimonious number of factors, sufficient items per factor, low inter-factor correlations and number of model misspecifications.

Results: All tested models showed adequate to excellent fit in respect to traditional model fit indices; however, models with two or more factors increasingly failed to meet other statistical and psychometric criteria.

Conclusion: Based on the results we favour a two-factor bifactor model with a strong general PTSD factor and two less dominant specific factors – one factor with trauma-related symptoms (re-experiencing and avoidance) and one factor with global psychological symptoms (describing the trauma’s higher-order impact on mood, cognition, behaviour and arousal).

From the perspective of clinical utility, we recommend the cut-off scoring method for the German version of the PCL-5. Basic psychometric properties and scale characteristics are provided.

HIGHLIGHTS

• We contribute new insights to the debate on the factor structure of the PTSD Checklist (PCL-5) based on a large German general population sample deploying the newest methodological developments in a revised factor-analytical approach.

• Combining theoretical, statistical and practical considerations, we favour a two-factor bifactor model with a strong general PTSD factor and two less dominant specific factors – one factor with trauma-related symptoms and one factor with global psychological symptoms.

• For clinical practitioners, we recommend using the cut-off scoring method.

Antecedentes: En un intento por dilucidar el Trastorno de Estrés Postraumático (TEPT), estudios analíticos factoriales recientes dieron como resultado modelos complejos con un número creciente de factores carentes de utilidad psicométrica y clínica. Recientemente, se han hecho sugerencias para optimizar las prácticas de análisis factorial para cumplir con un conjunto depurado de criterios estadísticos y psicométricos.

Objetivo: Este estudio apunta a evaluar la estructura factorial de la versión alemana del PCL-5, implementando avances metodológicos recientes para abordar el riesgo de sobreajuste de modelos. Al hacerlo, nos apartamos de la investigación analítica factorial tradicional sobre el TEPT.

Método: En una muestra a gran escala de la población general alemana (n = 1.625), se realizaron análisis factoriales exploratorios para investigar la dimensionalidad encontrada en los datos. Posteriormente, validamos y comparamos todas las sugerencias de modelos de nuestros análisis preliminares más todos los modelos factoriales de TEPT alternativos estándares y comunes (incluido el modelo CIE-11) de la literatura previa con análisis factoriales confirmatorios. No sólo consideramos índices de ajuste de modelos basados en la estimación WLSMV (mínimos cuadrados ponderados robustos con media y varianza ajustada), sino que también implementamos criterios como favorecer modelos menos complejos con un número parsimonioso de factores, suficientes elementos por factor, bajas correlaciones entre factores y un número de especificaciones erróneas del modelo.

Resultados: Todos los modelos probados mostraron un ajuste de adecuado a excelente con respecto a los índices de ajuste de modelos tradicionales; sin embargo, los modelos con dos o más factores fallaron progresivamente en cumplir con otros criterios estadísticos y psicométricos.

Conclusión: En base a los resultados, favorecemos un modelo bifactorial de dos factores con un fuerte factor de TEPT general y dos factores específicos menos dominantes: un factor con síntomas relacionados con el trauma (reexperimentación y evitación) y un factor con síntomas psicológicos globales (que describen el mayor impacto del trauma en el estado de ánimo, la cognición, el comportamiento y en el estado de alerta). Desde la perspectiva de la utilidad clínica, recomendamos el método de puntuación de corte para la versión alemana del PCL-5. Se proporcionan propiedades psicométricas básicas y características de la escala.

KEYWORDS:

• Post-traumatic stress disorder
• PCL-5
• LEC-5
• PTSD
• psychometric properties
• factorial structure

PALABRAS CLAVE:

• Trastorno de estrés postraumático
• PCL-5
• LEC-5
• TEPT
• propiedades psicométricas
• estructura factorial

Disclosure statement

During the revision of this work, the author used ChatGPT-3.5 in order to refine language. After using this tool, the authors reviewed and edited the content as needed and take full responsibility for the content of the publication. The authors reported no potential conflict of interest.

Data availability statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to the informed consent given by the participants.

Additional information

Funding

This work is funded by the Open Access Publishing Fund of Leipzig University supported by the German Research Foundation within the program Open Access Publication Funding.